Question:  

Is it allowed to perform voluntary Hajj on behalf of someone else?

Answer: 

If the person has already fulfilled the obligation (i.e. has already performed Hajj and `Umrah before), but now wants to appoint someone else to perform voluntary Hajj or `Umrah on his behalf; then concerning this matter there is a difference of opinion among the people of knowledge. Among them there are those who permit it and among them there are those who prohibit it. That which seems closest to what is correct with me is prohibition and that it is not permissible for anyone to appoint someone to perform Hajj or `Umrah on his behalf if it is voluntary. This is because the basic principle concerning acts of worship is that the person performs them by himself.

This is just as the person does not appoint someone to fast for him, even though if a person dies and he owes obligatory fast, his guardian or successor fasts on his behalf. The same is true concerning the Hajj, and the Hajj is an act of worship that the person is to perform with his body. Wealth given to someone else is not the intent of it. Since it is a bodily act of worship that the person performs with his body, it is not correct that someone else perform for him, except concerning what the Sunnah has reported. However, the Sunnah has not related anything concerning the person performing a voluntary Hajj on behalf of someone else. This is one of the two statements reported from Imaam Ahmad. I mean that it is not correct for the person to appoint someone else to perform voluntary Hajj or `Umrah for him, regardless of whether he is able to do it himself or not.

So, if we go by this statement, this becomes an encouragement to the wealthy people who are able to perform Hajj for themselves, because some people pass many years without even going to Makkah. They do this relying upon the act of appointing someone to perform Hajj for them every year. Thus, the person misses Hajj because he has appointed someone else to perform Hajj for him. And Allaah knows best. 

[Shaikh Ibn al-`Uthaymeen رحمه الله, Fataawaa Islaamiyah (2/192-193)]